Detection of the electromechanical delay and its components during voluntary isometric contraction of the quadriceps femoris muscle

Abstract

Electromechanical delay (EMD) was described as a time elapsed between first trigger and force output. Various results have been reported based on the measurement method with observed inconsistent results when the trigger is elicited by voluntary contraction. However, mechanomyographic (MMG) sensor placed far away on the skin from the contracting muscle was used to detect muscle fiber motion and excitation-contraction (EC) coupling which may give unreliable results. On this basis, the purpose of this study was to detect EMD during active muscle contraction whilst introducing an ultrafast ultrasound (US) method to detect muscle fiber motion from a certain depth of the muscle. Time delays between onsets of EMG-MMG, EMG-US, MMG-FORCE, US-FORCE, and EMG-FORCE were calculated as 20.5 ± 4.73, 28.63 ± 6.31, 19.21 ± 6.79, 30.52 ± 8.85, and 49.73 ± 6.99 ms, respectively. Intrarater correlation coefficient (ICC) was higher than MMG when ultrafast US was used for detecton of the Δt EMG-US and Δt US-FORCE, ICC values of 0.75 and 0.70, respectively. Synchronization of the ultrafast ultrasound with EMG and FORCE sensors can reveal reliable and clinically useful results related to the EMD and its components when muscle is voluntarily contracted. With ultrafast US, we detect onset from the certain depth of the muscle excluding the tissues above the muscle acting as a low-pass filter which can lead to inaccurate time detection about the onset of the contracting muscle fibers. With this non-invasive technique, understanding of the muscle dynamics can be facilitated.

Spontaneous mechanical and electrical activities of human calf musculature at rest assessed by repetitive single‐shot diffusion‐weighted MRI and simultaneous surface electromyography

“…Muscle contractile properties are often measured under active voluntary control or by surface electrode induced potentials (electrically evoked). For active isometric muscle contraction, an electromechanical delay of 49.73 6 7.99 ms has been reported in the literature (14), but it was also reported that electrically stimulated contractions show a significantly shorter electromechanical delay than voluntary contractions (16). Furthermore, each muscular activity has a specific contraction and relaxation time that is probably dependent on the composition of muscle fiber types.…”

Reaction time can be measured during voluntary contractions with electrode array

“…Torque signals were recorded at a sampling frequency of 4 kHz (PowerLab, AD Instruments, Australia) and were not filtered thereafter. Automated detection of EMG onset was first applied (threshold level: 3 SD) (Begovic et al, 2014). A 64-channel electrode array was positioned on the biceps femoris.…”

“…EMG signals were band-pass filtered (10-400 Hz, 2 nd -order Butterworth filter), then Teager-Kaiser energy operator was applied to improve signal-to-noise ratio and minimize erroneous EMG onset detection (Solnik et al, 2010). Automated detection of EMG onset was first applied (threshold level: 3 SD) (Begovic et al, 2014). Among all channels, the five fastest channels were visually inspected and only the first onset of EMG was retained for further analysis.…”

Changes in electromechanical delay during fatiguing dynamic muscle actions

“…Clinically, measurement of EMD has been used to examine the severity and progression of myotonic dystrophy and cerebral palsy, and Begovic et al . suggested that EMD along with ultrasound may be useful for tracking recovery from spinal/supraspinal injuries and to quantify these effects on the peripheral nervous system.…”

“…Clinically, measurement of EMD has been used to examine the severity and progression of myotonic dystrophy 5 and cerebral palsy, 8 and Begovic et al 9 suggested that EMD along with ultrasound may be useful for tracking recovery from spinal/ supraspinal injuries and to quantify these effects on the peripheral nervous system. Using electrical stimulation, Orizio et al 5 showed that patients with myotonic dystrophy exhibited greater EMD from the tibialis anterior than healthy controls due to elongated time durations associated with excitation-contraction coupling and the series elastic component.…”